This invention relates generally to a tuning system for firearms and more particularly to an adjustable mass tuning system for firearm barrels.
The precision of targeting a rifle can depend on a number of variables, such as the ability of the shooter/operator; the quality of the rifle; the caliber and quality of the ammunition; and the quality of the optical sighting systems. The precision of targeting the rifle can be measured as the rifle's ability to place repeated bullet shots within a known grouping size. The grouping size is typically measured in minutes of angle, or MOA, at a standard distance from the shooter, such as 100 yards. A rifle capable of one (1) MOA will repeatedly place shots in a 1-inch diameter circle at 100 yards, or 2-inches at 200 yards, etc.
Some rifle designs are inherently more precise than others. One factor that impacts precision is barrel dynamics, and a rifle with superior barrel dynamics can be more consistently accurate that an otherwise equivalent rifle with lesser barrel dynamics. The stiffer the barrel, the less it will distort and deviate from its initial aim point as a bullet is fired. A higher barrel stiffness generally requires a higher barrel mass; however, it is generally desirable for a high-powered rifle to be as light as possible. Thus, barrel stiffness is often limited by practical consideration in the rifle design.
To provide higher accuracy with lighter barrels, some shooters have experimented by modifying the powder loads of their ammunition in an attempt to time the exit of the bullet from the barrel muzzle to coincide with the barrel muzzle's lowest dynamic displacement. This method generally requires customized ammunition optimized for the specific firearm being used. Commercially available ammunition will typically not match the specifics required of the customized ammunition.
In an attempt to allow a given firearm to be tuned according to different ammunition, such as commercially available ammunition from multiple manufacturers, some shooters have developed dynamic tuning systems. One example is disclosed in U.S. Pat. No. 5,279,200 to Rose, which includes a moveable weight secured to the end of a gun barrel. The weight can be moved axially along the barrel to change damping characteristics and match the system to the ammunition.
Although Rose discusses damping characteristics and determining a “sweet spot” location, damping does not intrinsically alter the resonance vibration frequencies but only accelerates decay of the harmonic's amplitude. Further, the lateral displacement frequency is much lower than the longitudinal mode of barrel vibration by orders of magnitude and whose period is much too long be the cause of target aim diversion. In any case, the bullet muzzle exit event occurs over a time window much smaller than the highest frequency mode of barrel displacement. Therefore, it appears that damping is not the operative mechanism that improves rifle precision.
There remains a need for a robust mass tuning system for a firearm barrel that is highly adjustable, which can be set to a particular configuration that will not deviate over time and/or as the firearm is used repeatedly. There further remains a need for a mass tuning system that is uncomplicated for the end user.
All US patents and applications and all other published documents mentioned anywhere in this application are incorporated herein by reference in their entirety.
Without limiting the scope of the invention a brief summary of some of the claimed embodiments of the invention is set forth below. Additional details of the summarized embodiments of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below.
A brief abstract of the technical disclosure in the specification is provided as well only for the purposes of complying with 37 C.F.R. 1.72. The abstract is not intended to be used for interpreting the scope of the claims.